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1.
J Tissue Viability ; 2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-39054205

RESUMEN

Debridement is an important component of wound management and can improve outcomes for patients. Debridement needs to be done by an appropriately trained health professional, but the scope of practice, credentials, training, competencies, and regulatory requirements regarding wound debridement can differ. Best Practice Recommendations were created to positively influence patient safety related to all methods of debridement, across the continuum of care, and to be implemented widely by nurses at all professional levels in Canada. AIM: To further develop the Best Practice Recommendations for wound debridement, with an international perspective, by creating a consensus document to support the global adoption of evidence-based debridement practice for health professionals. METHODS: A consensus meeting utilising Delphi methods was conducted between the authors to review the consensus statements. Once 80 % agreement was achieved, a wide range of wound care experts were identified by the authors and invited to participate in an external review of the statements. RESULTS: Fifteen consensus statements about wound debridement were agreed upon and are presented in this paper. CONCLUSIONS: These best practice recommendations have been reviewed by a wide range of practitioners from across the UK and Canada and aim to provide guidance on the standardisation of debridement practices for healthcare professionals.

2.
Ann Oncol ; 28(9): 2305-2311, 2017 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-28911065

RESUMEN

BACKGROUND: Significant adverse events (AE) during cancer therapy disrupt treatment and escalate to emergency admissions. Approaches to improve the timeliness and accuracy of AE reporting may improve safety and reduce health service costs. Reporting AE via patient reported outcomes (PROs), can improve clinician-patient communication and making data available to clinicians in 'real-time' using electronic PROs (ePROs) could potentially transform clinical practice by providing easily accessible records to guide treatment decisions. This manuscript describes the development of eRAPID (electronic patient self-Reporting of Adverse-events: Patient Information and aDvice) is a National Institute for Health Research-funded programme, a system for patients to self-report and manage AE online during and after cancer treatment. MATERIALS AND METHODS: A multidisciplinary team of IT experts, staff and patients developed using agile principles a secure web application interface (QStore) between an existing online questionnaire builder (QTool) displaying real-time ePRO data to clinicians in the electronic patient record at Leeds Teaching Hospitals NHS Trust. Hierarchical algorithms were developed corresponding to Common Terminology Criteria for Adverse Events grading using the QTool question dependency function. Patient advocates (N = 9), patients (N = 13), and staff (N = 19) usability tested the system reporting combinations of AE. RESULTS: The eRAPID system allows patients to report AE from home on PC, tablet or any web enabled device securely during treatment. The system generates immediate self-management advice for low or moderate AE and for severe AE advice to contact the hospital immediately. Clinicians can view patient AE data in the electronic patient record and receive email notifications when patients report severe AE. CONCLUSIONS: Evaluation of the system in a randomised controlled trial in breast, gynaecological and colorectal cancer patients undergoing systemic therapy is currently underway. To adapt eRAPID for different treatment groups, pilot studies are being undertaken with patients receiving pelvic radiotherapy and upper gastrointestinal surgery. ISRCTN88520246.


Asunto(s)
Sistemas de Registro de Reacción Adversa a Medicamentos , Antineoplásicos/efectos adversos , Bases de Datos Factuales , Registros Electrónicos de Salud , Neoplasias/tratamiento farmacológico , Autoinforme , Integración de Sistemas , Algoritmos , Humanos
4.
Nat Genet ; 17(4): 498-502, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9398860

RESUMEN

The maintenance of chromosome termini, or telomeres, requires the action of the enzyme telomerase, as conventional DNA polymerases cannot fully replicate the ends of linear molecules. Telomerase is expressed and telomere length is maintained in human germ cells and the great majority of primary human tumours. However, telomerase is not detectable in most normal somatic cells; this corresponds to the gradual telomere loss observed with each cell division. It has been proposed that telomere erosion eventually signals entry into senescence or cell crisis and that activation of telomerase is usually required for immortal cell proliferation. In addition to the human telomerase RNA component (hTR; ref. 11), TR1/TLP1 (refs 12, 13), a protein that is homologous to the p80 protein associated with the Tetrahymena enzyme, has been identified in humans. More recently, the human telomerase reverse transcriptase (hTRT; refs 15, 16), which is homologous to the reverse transcriptase (RT)-like proteins associated with the Euplotes aediculatus (Ea_p123), Saccharomyces cerevisiae (Est2p) and Schizosaccharomyces pombe (5pTrt1) telomerases, has been reported to be a telomerase protein subunit. A catalytic function has been demonstrated for Est2p in the RT-like class but not for p80 or its homologues. We now report that in vitro transcription and translation of hTRT when co-synthesized or mixed with hTR reconstitutes telomerase activity that exhibits enzymatic properties like those of the native enzyme. Single amino-acid changes in conserved telomerase-specific and RT motifs reduce or abolish activity, providing direct evidence that hTRT is the catalytic protein component of telomerase. Normal human diploid cells transiently expressing hTRT possessed telomerase activity, demonstrating that hTRT is the limiting component necessary for restoration of telomerase activity in these cells. The ability to reconstitute telomerase permits further analysis of its biochemical and biological roles in cell aging and carcinogenesis.


Asunto(s)
ADN Polimerasa Dirigida por ARN/genética , ADN Polimerasa Dirigida por ARN/metabolismo , ARN/metabolismo , Telomerasa/genética , Secuencia de Aminoácidos , Animales , Catálisis , Humanos , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , ARN/biosíntesis , ARN/genética , ADN Polimerasa Dirigida por ARN/biosíntesis , Conejos , Alineación de Secuencia , Moldes Genéticos
5.
J Exp Biol ; 213(Pt 16): 2851-64, 2010 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-20675555

RESUMEN

Animals must negotiate obstacles in their path in order to successfully function within natural environments. These actions require transitions from walking to other behaviors, many of which are more involved than simple reflexes. For these behaviors to be successful, insects must evaluate objects in their path and then use that information to change posture or re-direct leg movements. Some of this control may occur within a region of the brain known as the central complex (CC). We used discrete electrolytic lesions to examine the role of certain sub-regions of the CC in various obstacle negotiation behaviors. We found that cockroaches with lesions to the protocerebral bridge (PB) and ellipsoid body (EB) exhibit abnormalities in turning and dealing with shelf-like objects; whereas, individuals with lesions to the fan-shaped body (FB) and lateral accessory lobe (LAL), exhibit abnormalities of those behaviors as well as climbing over blocks and up walls to a horizontal plane. Abnormalities in block climbing include decreased success rate, changes in climbing strategy, and delayed response to the block. Increases in these abnormal behaviors were significant in individuals with lesions to the FB and LAL. Although turning abnormalities are present in individuals with lesions to the LAL, EB and the lateral region of the FB, there are some differences in how these deficits present. For instance, the turning deficits seen in individuals with lateral FB lesions only occurred when turning in the direction opposite to the side of the brain on which the lesion occurred. By contrast, individuals with lesions to the EB and LAL exhibited turning abnormalities in both directions. Lesions in the medial region of the FB did not result in directional turning deficits, but in abnormalities in block climbing.


Asunto(s)
Conducta Animal/fisiología , Cucarachas , Actividad Motora/fisiología , Animales , Encéfalo/anatomía & histología , Encéfalo/patología , Encéfalo/fisiología , Cucarachas/anatomía & histología , Cucarachas/fisiología , Extremidades/anatomía & histología , Extremidades/fisiología , Movimiento , Neurópilo/citología , Neurópilo/patología , Neurópilo/fisiología , Postura/fisiología
6.
J Neuropsychiatry Clin Neurosci ; 22(1): 105-10, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20160217

RESUMEN

Using 10 years' enrollment history, patients with non-drug-induced Parkinson's disease were identified, and the prevalence of Parkinson's disease-induced psychosis (PDP) was estimated using three different claims algorithms based on an expert working group criteria. The estimated prevalence of PDP ranged from 4 to 45/1,000 Parkinson's disease patients. PDP patients were just as likely to be male as female and were significantly older than Parkinson's disease patients without PDP. PDP patients more commonly had evidence of dementia and use of atypical antipsychotics. PDP occurs in up to 45,000 Parkinson's disease patients in the United States but represents a unique neuropsychiatric finding with important treatment implications.


Asunto(s)
Programas Controlados de Atención en Salud/estadística & datos numéricos , Enfermedad de Parkinson/psicología , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/etiología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Vigilancia de la Población/métodos , Prevalencia , Trastornos Psicóticos/epidemiología , Estados Unidos/epidemiología
7.
Sci Rep ; 10(1): 8176, 2020 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-32424237

RESUMEN

The glass sponge Aphrocallistes vastus contributes to the formation of large reefs unique to the Northeast Pacific Ocean. These habitats have tremendous filtration capacity that facilitates flow of carbon between trophic levels. Their sensitivity and resilience to climate change, and thus persistence in the Anthropocene, is unknown. Here we show that ocean acidification and warming, alone and in combination have significant adverse effects on pumping capacity, contribute to irreversible tissue withdrawal, and weaken skeletal strength and stiffness of A. vastus. Within one month sponges exposed to warming (including combined treatment) ceased pumping (50-60%) and exhibited tissue withdrawal (10-25%). Thermal and acidification stress significantly reduced skeletal stiffness, and warming weakened it, potentially curtailing reef formation. Environmental data suggests conditions causing irreversible damage are possible in the field at +0.5 °C above current conditions, indicating that ongoing climate change is a serious and immediate threat to A. vastus, reef dependent communities, and potentially other glass sponges.


Asunto(s)
Arrecifes de Coral , Calentamiento Global , Poríferos/crecimiento & desarrollo , Animales , Cambio Climático , Ecosistema , Concentración de Iones de Hidrógeno , Fuerza Muscular , Músculo Esquelético/fisiología , Océano Pacífico , Poríferos/fisiología , Agua de Mar/química
8.
Neuroscience ; 158(4): 1277-83, 2009 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-19041926

RESUMEN

The role protein phosphatase 2B (calcineurin, CaN) plays in learning and memory has received a significant amount of attention due to its promotion of the dephosphorylation of 3'-5'-cyclic AMP response element binding protein (CREB). Researchers have ascertained that overexpression of CaN is associated with memory retention deficits [Foster TC, Sharrow KM, Masse JR, Norris CM, Kumar A (2001) Calcineurin links Ca(2+) dysregulation with brain aging. J Neurosci 21:4066-4073; Mansuy IM, Mayford M, Jacob B, Kandel ER, Bach ME (1998) Restricted and regulated overexpression reveals calcineurin as a key component in the transition from short-term to long-term memory. Cell 92:39-49], while CaN inhibition enhances learning and memory [Gerdjikov TV, Beninger RJ (2005) Differential effects of calcineurin inhibition and protein kinase A activation on nucleus accumbens amphetamine-produced conditioned place preference in rats. Eur J Neurosci 22:697-705; Ikegami S, Inokuchi K (2000) Antisense DNA against calcineurin facilitates memory in contextual fear conditioning by lowering the threshold for hippocampal long-term potentiation induction. Neuroscience 98:637-646]. The present study hypothesized that infusion of a CaN inhibitor (FK506) bilaterally into the olfactory bulbs of postnatal day 6 Sprague Dawley rat pups would prolong the duration of a conditioned odor preference and retard cyclic AMP response element binding protein dephosphorylation. A 2 mg/kg s.c. injection of isoproterenol (ISO, beta-adrenoceptor agonist) was paired with a 10 min exposure to peppermint and subsequently an infusion of FK506. Immunohistochemistry for phosphorylated 3'-5'-cyclic AMP response element binding protein (pCREB) revealed that unilateral infusion of FK506 resulted in an amplification of phosphorylated CREB in the olfactory bulb 40 min after training compared with saline-infused bulbs. Pups infused bilaterally with FK506 maintained a learned preference for peppermint 48, 72 and 96 h after training. CaN inhibition also modified the conventional inverted U curve obtained when ISO is used to replace stroking, as the unconditioned stimulus. When pups were infused with FK506, learning occurred with sub- and supra-optimal doses of ISO indicating that CaN overcomes non-optimal effects ISO may have on learning. We demonstrate that CaN inhibition can extend the duration of conditioned olfactory memory and may provide a target for memory prolongation that is superior to even phosphodiesterase inhibition observed in previous studies.


Asunto(s)
Inhibidores de la Calcineurina , Condicionamiento Psicológico/fisiología , AMP Cíclico/metabolismo , Memoria/fisiología , Agonistas Adrenérgicos beta/farmacología , Análisis de Varianza , Animales , Animales Recién Nacidos , Proteína de Unión a CREB/metabolismo , Condicionamiento Psicológico/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Isoproterenol/farmacología , Memoria/efectos de los fármacos , Odorantes , Bulbo Olfatorio/efectos de los fármacos , Bulbo Olfatorio/metabolismo , Fosforilación/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Tacrolimus/farmacología , Factores de Tiempo
9.
J Cell Biol ; 134(1): 1-12, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8698806

RESUMEN

Telomeres have been shown to gradually shorten during replicative aging in human somatic cells by Southern analysis. This study examines telomere shortening at the single cell level by fluorescence in situ hybridization (FISH). FISH and confocal microscopy of interphase human diploid fibroblasts (HDFs) demonstrate that telomeres are distributed throughout the nucleus with an interchromosomal heterogeneity in size. Analysis of HDFs at increasing population doubling levels shows a gradual decrease in spot size, intensity, and detectability of telomeric signal. FISH of metaphase chromosomes prepared from young and old HDFs shows a heterogeneity in detection frequency for telomeres on chromosomes 1, 9, 15, and Y. The interchromosomal distribution of detection frequencies was similar for cells at early and late passage. The telomeric detection frequency for metaphase chromosomes also decreased with age. These observations suggest that telomeres shorten at similar rates in normal human somatic cels. T-antigen transformed HDFs near crisis contained telomere signals that were low compared to nontransformed HDFs. A large intracellular heterogeneity in telomere lengths was detected in two telomerase-negative cell lines compared to normal somatic cells and the telomerase-positive 293 cell line. Many telomerase-negative immortal cells had telomeric signals stronger than those in young HDFs, suggesting a different mechanism for telomere length regulation in telomerase-negative immortal cells. These studies provide an in situ demonstration of interchromosomal heterogeneity in telomere lengths. Furthermore, FISH is a reliable and sensitive method for detecting changes in telomere size at the single cell level.


Asunto(s)
Transformación Celular Viral , Senescencia Celular , Telómero/ultraestructura , División Celular , Células Cultivadas , Humanos , Hibridación Fluorescente in Situ , Virus 40 de los Simios
10.
Science ; 207(4427): 191-3, 1980 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-7350654

RESUMEN

The commitment theory of human fibroblast aging predicts that 55 percent of cells will be nondividing at the middle to late stages of the replicative lifespan; in the present study, however, fewer than 10 percent were nondividing. The fact that no immortal diploid cells have yet been reported is also at odds with the theory. Available data on the variable life-span of clones and mass cultures, the dependence of longevity on population size, and the predominance of certain cell types at termination of a culture are compatible with simpler theories, which support the idea that the limited replicative life-span of diploid fibroblasts is a valid model for organismic aging.


Asunto(s)
División Celular , Supervivencia Celular , Células Cultivadas/citología , Diferenciación Celular , Probabilidad
11.
Science ; 277(5328): 955-9, 1997 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-9252327

RESUMEN

Catalytic protein subunits of telomerase from the ciliate Euplotes aediculatus and the yeast Saccharomyces cerevisiae contain reverse transcriptase motifs. Here the homologous genes from the fission yeast Schizosaccharomyces pombe and human are identified. Disruption of the S. pombe gene resulted in telomere shortening and senescence, and expression of mRNA from the human gene correlated with telomerase activity in cell lines. Sequence comparisons placed the telomerase proteins in the reverse transcriptase family but revealed hallmarks that distinguish them from retroviral and retrotransposon relatives. Thus, the proposed telomerase catalytic subunits are phylogenetically conserved and represent a deep branch in the evolution of reverse transcriptases.


Asunto(s)
Proteínas/química , ARN , Schizosaccharomyces/enzimología , Telomerasa/química , Secuencia de Aminoácidos , Sitios de Unión , Catálisis , Línea Celular , Proteínas de Unión al ADN , Evolución Molecular , Genes Fúngicos , Humanos , Intrones , Datos de Secuencia Molecular , Filogenia , Proteínas/genética , Proteínas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , ADN Polimerasa Dirigida por ARN/química , Retroelementos , Schizosaccharomyces/genética , Schizosaccharomyces/crecimiento & desarrollo , Proteínas de Schizosaccharomyces pombe , Alineación de Secuencia , Telomerasa/genética , Telomerasa/metabolismo , Telómero/metabolismo
12.
Science ; 266(5193): 2011-5, 1994 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-7605428

RESUMEN

Synthesis of DNA at chromosome ends by telomerase may be necessary for indefinite proliferation of human cells. A highly sensitive assay for measuring telomerase activity was developed. In cultured cells representing 18 different human tissues, 98 of 100 immortal and none of 22 mortal populations were positive for telomerase. Similarly, 90 of 101 biopsies representing 12 human tumor types and none of 50 normal somatic tissues were positive. Normal ovaries and testes were positive, but benign tumors such as fibroids were negative. Thus, telomerase appears to be stringently repressed in normal human somatic tissues but reactivated in cancer, where immortal cells are likely required to maintain tumor growth.


Asunto(s)
ADN Nucleotidilexotransferasa/metabolismo , Neoplasias/enzimología , Secuencia de Bases , División Celular , Línea Celular , Línea Celular Transformada/enzimología , Activación Enzimática , Represión Enzimática , Femenino , Humanos , Masculino , Datos de Secuencia Molecular , Ovario/enzimología , Reacción en Cadena de la Polimerasa , Testículo/enzimología , Células Tumorales Cultivadas
13.
Science ; 279(5349): 349-52, 1998 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-9454332

RESUMEN

Normal human cells undergo a finite number of cell divisions and ultimately enter a nondividing state called replicative senescence. It has been proposed that telomere shortening is the molecular clock that triggers senescence. To test this hypothesis, two telomerase-negative normal human cell types, retinal pigment epithelial cells and foreskin fibroblasts, were transfected with vectors encoding the human telomerase catalytic subunit. In contrast to telomerase-negative control clones, which exhibited telomere shortening and senescence, telomerase-expressing clones had elongated telomeres, divided vigorously, and showed reduced straining for beta-galactosidase, a biomarker for senescence. Notably, the telomerase-expressing clones have a normal karyotype and have already exceeded their normal life-span by at least 20 doublings, thus establishing a causal relationship between telomere shortening and in vitro cellular senescence. The ability to maintain normal human cells in a phenotypically youthful state could have important applications in research and medicine.


Asunto(s)
División Celular , Senescencia Celular , Proteínas/metabolismo , ARN , Telomerasa/metabolismo , Telómero/fisiología , Biomarcadores , Catálisis , Línea Celular , Transformación Celular Neoplásica , Clonación Molecular , Proteínas de Unión al ADN , Fibroblastos/citología , Homeostasis , Humanos , Cariotipificación , Fenotipo , Epitelio Pigmentado Ocular/citología , Proteínas/genética , ADN Polimerasa Dirigida por ARN/genética , ADN Polimerasa Dirigida por ARN/metabolismo , Células Madre/citología , Células Madre/enzimología , Telomerasa/genética , Telómero/metabolismo , Telómero/ultraestructura , Transfección , Células Tumorales Cultivadas , beta-Galactosidasa/metabolismo
14.
Curr Opin Genet Dev ; 5(2): 249-55, 1995 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-7613096

RESUMEN

Telomeres are maintained by the novel ribonucleoprotein enzyme telomerase. Telomerase activity is repressed in most somatic human cells, leading to telomere loss during replicative aging in vivo and in vitro. However, telomerase appears to be reactivated in essentially all human cancers. With the recent cloning of the RNA component of telomerase from several species, the stage is now set for critical tests of the role of telomeres and telomerase in aging and cancer.


Asunto(s)
Envejecimiento/genética , ADN Nucleotidilexotransferasa/metabolismo , Neoplasias/genética , Telómero , Envejecimiento/metabolismo , Animales , Secuencia de Bases , ADN , Humanos , Datos de Secuencia Molecular , Neoplasias/enzimología , Células Madre/metabolismo
15.
Int J Clin Pract ; 62(6): 889-95, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18479282

RESUMEN

BACKGROUND: Previous studies have demonstrated that failure to reach National Cholesterol Education Program (NCEP) target low-density lipoprotein cholesterol (LDL-C) goal increases the risk of cardiovascular events. Ability to meet goal may be impacted by the choice of statin therapy. PURPOSE: This study compares rosuvastatin to other statin therapies among patients presenting with risk factors associated with failure to reach NCEP goal. METHODS: Retrospective analysis using medical and pharmacy claims linked to laboratory results from a national health plan encompassing private and MedicareAdvantage enrollees age > or = 18 years and newly treated with statins from 1 August 2003 to 28 February 2005. Predictors of failure to reach goal were statin treatment group, age, gender, NCEP risk level, per cent reduction required to attain goal and days from index to LDL-C measurement. RESULTS: Of 11,814 eligible patients, 9.6% were initiated on rosuvastatin, 54.2% atorvastatin, 17.9% simvastatin, 7.1% pravastatin, 2.0% fluvastatin and 9.3% lovastatin. Independent predictors of failure to reach goal included > or = 15% LDL-C reduction required to reach goal, and high and moderate NCEP risk status. In the subset of patients at higher risk of failure to reach goal, rosuvastatin demonstrated a significantly lower rate of failure to achieve goal than atorvastatin, simvastatin, pravastatin, fluvastatin or lovastatin. CONCLUSIONS: Real-world factors associated with high risk of failure to reach goal may be used in identifying patients more likely to succeed on rosuvastatin compared with other statins. Low-risk patients needing < 15% LDL-C reduction would be suitable candidates for initiation of most other statins, specifically simvastatin, which has recently become available in the generic form.


Asunto(s)
Fluorobencenos/uso terapéutico , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Hipercolesterolemia/tratamiento farmacológico , Pirimidinas/uso terapéutico , Sulfonamidas/uso terapéutico , Enfermedades Cardiovasculares/sangre , LDL-Colesterol/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Rosuvastatina Cálcica , Resultado del Tratamiento
16.
Appl Physiol Nutr Metab ; 43(3): 274-281, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29065278

RESUMEN

Despite the growing quantity of literature exploring the effect of caffeine on muscular strength, there is a dearth of data that directly explores differences in erogenicity between upper and lower body musculature and the dose-response effect. The present study sought to investigate the effects of low and moderate doses of caffeine on the maximal voluntary strength of the elbow flexors and knee extensors. Ten nonspecifically strength-trained, recreationally active participants (aged 21 ± 0.3 years) completed the study. Using a randomised, counterbalanced, and double-blind approach, isokinetic concentric and eccentric strength was measured at 60 and 180°/s following administration of a placebo, 3 mg·kg-1 body mass caffeine, and 6 mg·kg-1 body mass caffeine. There was no effect of caffeine on the maximal voluntary concentric and eccentric strength of the elbow flexors, or the eccentric strength of the knee extensors. Both 3 and 6 mg·kg-1 body mass caffeine caused a significant increase in peak concentric force of the knee extensors at 180°/s. No difference was apparent between the 2 concentrations. Only 6 mg·kg-1 body mass caused an increase in peak concentric force during repeated contractions. The results infer that the effective caffeine concentration to evoke improved muscle performance may be related to muscle mass and contraction type. The present work indicates that a relatively low dose of caffeine treatment may be effective for improving lower body muscular strength, but may have little benefit for the strength of major muscular groups of the upper body.


Asunto(s)
Cafeína/administración & dosificación , Cafeína/farmacología , Fuerza Muscular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Masculino , Percepción del Dolor/efectos de los fármacos , Adulto Joven
17.
J Clin Invest ; 68(4): 988-94, 1981 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7026617

RESUMEN

To determine whether old cells have a reduced response to a preparation of factors from human plasma with insulinlike activity (ILA), we analyzed the response to ILA of early and late passage human fibroblasts from young, old, and progeric donors in the acute stimulation of [3H]2-deoxy-D-glucose (2dG) uptake and the delayed stimulation of [3H]thymidine (TdR) incorporation into DNA. The ILA concentration required to produce equivalent, relative stimulation of TdR incorporation was increased two- to three-fold in late passage cells and cells from old and progeric donors (P less than 0.01). 50 and 95% of maximal stimulation (ILA50, ILA95) was achieved by 0.26 +/- 0.07 and 1.38 +/- 0.13 ng insulin equivalents/ml (mean +/- SD) respectively, in cells from young adults at early passage. Corresponding values were 0.54 +/- 0.05 and 2.90 +/- 0.25 in cells from old donors; greater than 0.9 +/- 0.1 and greater than 3.1 +/- 0.1 in cells from a 9-yr-old progeric donor; and 0.4 +/- 0.05 and 1.1 +/- 0.04 in cells from normal children (9-13 yr). For two cell strains from young adults, ILA50 and ILA95 were 0.30 +/- 0.02 and 1.0 +/- 0.3 ng eq/ml at 30% of their in vitro lifespan completed (%LC) and these values increased at rates of 0.005 ng eq/ml per %LC and 0.04 ng eq/ml per %LC, respectively. The mean stimulation of 2dG uptake ratio (ILA/control) decreased from early to late passage from 2.1 +/- 0.6 to 1.3 +/- 0.1 in young adult donors (P less than 0.05), but there were no significant differences between young and old donors at either early or late passage. The mean stimulation ratio in progeric cells (1.2 +/- 0.2) did not change with in vitro passage, but was significantly lower than that of age-matched normal cells (2.1 +/- 0.8, P less than 0.001). In progeria cells, the reduced stimulation of 2dG uptake upon addition of ILA was due to an increased basal rate of uptake (0.19 +/- 0.01 pmol [3H]2dG/min per mg protein vs. 0.13 +/- 0.01 in age-matched normal cells), and not to a decline in the maximal rate of uptake (0.26 +/- 0.01 vs. 0.27 +/- 0.02, respectively). Similar results were found for in vitro aging in cells from an old donor.


Asunto(s)
Envejecimiento , Desoxiazúcares/metabolismo , Desoxiglucosa/metabolismo , Sustancias de Crecimiento/farmacología , Insulina/farmacología , Progeria/metabolismo , Adolescente , Adulto , Anciano , Transporte Biológico/efectos de los fármacos , División Celular/efectos de los fármacos , Niño , Sustancias de Crecimiento/sangre , Humanos
18.
J Clin Invest ; 89(5): 1662-8, 1992 May.
Artículo en Inglés | MEDLINE | ID: mdl-1569205

RESUMEN

Transforming growth factor beta (TGF beta) is a multifunctional protein which has been suggested to play a central role in the pathogenesis of chronic inflammation and fibrosis. Nasal polyposis is a condition affecting the upper airways characterized by the presence of chronic inflammation and varying degrees of fibrosis. To examine the potential role of TGF beta in the pathogenesis of this condition, we investigated gene expression and cytokine production in nasal polyp tissues as well as in the normal nasal mucosa. By Northern blot analysis using a porcine TGF beta 1 cDNA probe, we detected TGF beta 1-specific mRNA in nasal polyp tissues, as well as in the tissue from a patient with allergic rhinitis, but not in the normal nasal mucosa. By the combination of tissue section staining with chromotrope 2R with in situ hybridization using the same TGF beta 1 probe, we found that approximately 50% of the eosinophils infiltrating the polyp tissue express the TGF beta 1 gene. In addition, immunohistochemical localization of TGF beta 1 was detected associated with extracellular matrix as well as in cells in the stroma. These results suggest that in nasal polyposis where eosinophils are the most prevalent inflammatory cell, TGF beta 1 synthesized by these cells may contribute to the structural abnormalities such as stromal fibrosis and basement membrane thickening which characterize this disease.


Asunto(s)
Eosinófilos/fisiología , Pólipos Nasales/fisiopatología , Factor de Crecimiento Transformador beta/genética , Enfermedad Crónica , Expresión Génica , Humanos , Inflamación/fisiopatología , Hibridación de Ácido Nucleico , ARN Mensajero/genética
19.
Mol Cell Biol ; 9(5): 2279-83, 1989 May.
Artículo en Inglés | MEDLINE | ID: mdl-2568584

RESUMEN

The complete cDNA for a human mitochondrial protein designated P1, which was previously identified as a microtubule-related protein, has been cloned and sequenced. The deduced amino acid sequence of P1 shows strong homology (40 to 50% identical residues and an additional 20% conservative replacements) to the 65-kilodalton major antigen of mycobacteria, to the GroEL protein of Escherichia coli, and to the ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) subunit binding protein of plant chloroplasts. Similar to the case with the latter two proteins, which have been shown to act as chaperonins in the posttranslational assembly of oligomeric protein structures, it is suggested that P1 may play a similar role in mammalian cells. The observed high degree of homology between human P1 and mycobacterial antigen also suggests the possible involvement of this protein in certain autoimmune diseases.


Asunto(s)
Proteínas Bacterianas/genética , Proteínas de Choque Térmico/genética , Proteínas Asociadas a Microtúbulos/genética , Proteínas de Plantas/genética , Plantas/genética , Secuencia de Aminoácidos , Antígenos Bacterianos/genética , Bacterias/genética , Secuencia de Bases , Chaperonina 60 , Chaperoninas , ADN/genética , Humanos , Proteínas Mitocondriales , Datos de Secuencia Molecular , Mycobacterium/genética
20.
Mol Biol Cell ; 11(4): 1345-56, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10749934

RESUMEN

An evolutionarily ancient mechanism is used for intracellular membrane fusion events ranging from endoplasmic reticulum-Golgi traffic in yeast to synaptic vesicle exocytosis in the human brain. At the heart of this mechanism is the core complex of N-ethylmaleimide-sensitive fusion protein (NSF), soluble NSF attachment proteins (SNAPs), and SNAP receptors (SNAREs). Although these proteins are accepted as key players in vesicular traffic, their molecular mechanisms of action remain unclear. To illuminate important structure-function relationships in NSF, a screen for dominant negative mutants of yeast NSF (Sec18p) was undertaken. This involved random mutagenesis of a GAL1-regulated SEC18 yeast expression plasmid. Several dominant negative alleles were identified on the basis of galactose-inducible growth arrest, of which one, sec18-109, was characterized in detail. The sec18-109 phenotype (abnormal membrane trafficking through the biosynthetic pathway, accumulation of a membranous tubular network, growth suppression, increased cell density) is due to a single A-G substitution in SEC18 resulting in a missense mutation in Sec18p (Thr(394)-->Pro). Thr(394) is conserved in most AAA proteins and indeed forms part of the minimal AAA consensus sequence that serves as a signature of this large protein family. Analysis of recombinant Sec18-109p indicates that the mutation does not prevent hexamerization or interaction with yeast alpha-SNAP (Sec17p), but instead results in undetectable ATPase activity that cannot be stimulated by Sec17p. This suggests a role for the AAA protein consensus sequence in regulating ATP hydrolysis. Furthermore, this approach of screening for dominant negative mutants in yeast can be applied to other conserved proteins so as to highlight important functional domains in their mammalian counterparts.


Asunto(s)
Adenosina Trifosfatasas , Adenosina Trifosfato/metabolismo , Proteínas Fúngicas/genética , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Proteínas de Transporte Vesicular , Secuencia de Aminoácidos , Línea Celular , Secuencia de Consenso , Escherichia coli/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Humanos , Hidrólisis , Membranas Intracelulares/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis , Mutación Missense , Plásmidos , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/metabolismo , Alineación de Secuencia
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